I am trying to draw a transparent CALayer in a UITextView in order to highlight matched text in a search.
I've figured out the correct way to do this, but still haven't found the correct coordinates. I need to find the origin of the text container. Right now, I get the textView's origin, and offset the layer's origin by that:
NSRange match = [[[self textView]text]rangeOfString:@"predict the future"];
NSRange glyphRange = [manager glyphRangeForCharacterRange:match actualCharacterRange:NULL];
CGRect textRect = [manager boundingRectForGlyphRange:glyphRange inTextContainer:[[self textView]textContainer]];
CGPoint textViewOrigin = self.textView.frame.origin;
textRect.origin.x += (textViewOrigin.x / 2);
textRect.origin.y += (textViewOrigin.y / 2);
CALayer* roundRect = [CALayer layer];
[roundRect setFrame:textRect];
[roundRect setBounds:textRect];
[roundRect setCornerRadius:5.0f];
[roundRect setBackgroundColor:[[UIColor blueColor]CGColor]];
[roundRect setOpacity:0.2f];
[roundRect setBorderColor:[[UIColor blackColor]CGColor]];
[roundRect setBorderWidth:3.0f];
[roundRect setShadowColor:[[UIColor blackColor]CGColor]];
[roundRect setShadowOffset:CGSizeMake(20.0f, 20.0f)];
[roundRect setShadowOpacity:1.0f];
[roundRect setShadowRadius:10.0f];
[[[self textView]layer]addSublayer:roundRect];
I get the following result if I move the text field, or if I don't divide the offsets by 2:
I'd like to know if i'm on the right track and also how to find the NSTextContainer object's origin if so.